Micro bump structure (μbump) is one of the key technologies in multiple die module (MDM), system in package (SIP), or multi-chip-module (MCM) (hereinafter multi-die interconnect architecture.) A common multi-die interconnect often includes hundreds of thousands or millions of μbumps between two semiconductor dies, whereas ensuring 100% yield of all the μbumps is unrealistic. Thus, it is not uncommon to have one or more faulty μbump(s) in a device.
Examples of a faulty μbump includes but are not limited to: missing μbump, deformation of a μbump, an under-sized μbump, a partially formed μbump, or damaged μbump (e.g., cracked or broken μbump), wherein each of these may result in an open connection. A μbump may also be considered faulty if it is connected to a broken trace, or to a faulty circuit, which prevents the μbump from transmitting and/or receiving signals. Also, μbumps may fail due to wear and tear over time or due to environmental effects such as those arising from temperature fluctuations. Some faulty μbumps may be marginally functional. For example, these μbumps may function as intended at certain temperature range and may malfunction at some other temperature range. Sometimes, an interposer that includes a plurality of μbumps may be used to connect two dies. Such interposer may also have faulty μbump(s).
As used in this specification, the term “faulty μbump” may refer to any μbump that fails to perform according to a pre-defined criteria, any μbump that is unacceptable, or any μbump (which may be perfect itself) that does not transmit and/or receive signals due to a faulty trace or circuit connecting to the μbump. Thus, a faulty μbump may be due to any failure mode, including but not limited to the examples mentioned previously.
Redundancy is a method for compensating for a failing or failed resource by having extra unit(s) of a resource to replace the failed or failing resource with one or more of the extra unit(s) of the resource to restore the intended functionality of the failed or failing resource.
The conventional redundancy techniques give rise to various disadvantages and difficulties. Therefore, it is desirable to have a more flexible and robust method and apparatus for providing redundancy in multi-die interconnect.